# Neutrino 2018 - XXVIII International Conference on Neutrino Physics and Astrophysics

4-9 June 2018
Heidelberg
Europe/Berlin timezone
Home > Timetable > Session details > Contribution details

# Contribution Poster model building

Poster (not participating in poster prize competition)

# Precision neutrino data confronts $\mu\leftrightarrow\tau$ symmetry

## Speakers

• Mr. Uma Sankar S.

## Session and Location

Wednesday Session, Poster Wall #146 (Hölderlin-Room)

## Abstract content

The neutrino mixing angles are predicted to be $\theta_{23}=-\pi/4$ and $\theta_{13}=0$ if the neutrino mass matrix has $\mu\leftrightarrow\tau$ exchange symmetry. We need to break this symmetry to obtain a match with experimental measurements. This breaking is given by two parameters: $\varepsilon_1$ and $\varepsilon_2$. We show that the magnitude of $\theta_{13}$ is controlled by $\varepsilon_1$ whereas the deviation of $\theta_{23}$ from maximality is controlled by $\varepsilon_2$. The measured value of $\theta_{13}$ requires $\mu\leftrightarrow\tau$ symmetry to be badly broken for both normal hierarchy and inverted hierarchy, though the level of breaking depends sensitively on the hierarchy. We also find that the precision oscillation data constrains all elements of neutrino mass matrix to be in very narrow ranges. In the case of inverted hierarchy, we find that $\mu\leftrightarrow -\tau$ exchange symmetry provides an explanation of neutrino mixing angles with some fine-tuning.

yes